Ultrasonic sonothrombolysis treatment planning

Abstract

An ultrasound system utilizes an array transducer to perform sonothrombolysis treatment. The system also produces a vascular map of flow characteristics in the vicinity of the therapy site in a subject. The vascular map is used to formulate a treatment plan which includes the number, focusing, timing, and steering of beams of a pattern of therapy beams transmitted during a transmission interval. Formulation of the treatment plan considers factors such as the direction of microbubble flow toward a therapy site, the flow velocity, the spacing between successive therapy beam transmissions, the number of therapy beams needed to “paint” a therapy region, and grating lobe locations, many of which can be determined from the vascular map.

1 . An ultrasound system adapted to perform therapy on a subject comprising:
 an array of transducer elements, configured to transmit a plurality of therapeutic ultrasonic energy beams aimed at a therapeutic site;   a diagnostic imaging modality which is adapted to produce a vascular map of the therapeutic site, the vascular map comprising a volume rendering of flow signals acquired at the therapeutic site;   a therapy beam transmit controller, responsive to a treatment plan formulated in consideration of the flow signals, which is adapted to transmit a variable sequence of differently steered therapy beams to the therapeutic site during a plurality of transmission intervals.   
     
     
         2 . The ultrasound system of  claim 1 , wherein the treatment plan is further formulated to determine an order in which the differently steered therapy beams are transmitted. 
     
     
         3 . The ultrasound system of  claim 2 , wherein the treatment plan is further formulated to determine a number of differently steered therapy beams which are transmitted. 
     
     
         4 . The ultrasound system of  claim 3 , wherein the treatment plan is further formulated to determine a length of a pause between successive transmission intervals. 
     
     
         5 . The ultrasound system of  claim 4  wherein the length of the pause between successive transmission intervals is determined in consideration of a flow velocity identified by the vascular map. 
     
     
         6 . The ultrasound system of  claim 2 , wherein the treatment plan is further formulated to determine the order in which the differently steered therapy beams are transmitted in consideration of a flow direction identified by the vascular map. 
     
     
         7 . The ultrasound system of  claim 6 , wherein the treatment plan is further formulated to determine the order in which the differently steered therapy beams so that a later-transmitted beam in the sequence is upstream in relation to the flow direction from an earlier-transmitted beam. 
     
     
         8 . The ultrasound system of  claim 2 , wherein the treatment plan is further formulated to determine the order in which the differently steered therapy beams are transmitted in consideration of a spacing between successively transmitted therapy beams. 
     
     
         9 . The ultrasound system of  claim 2 , wherein the treatment plan is further formulated to determine the order in which the differently steered therapy beams are transmitted in consideration of grating lobes of the steered therapy beams. 
     
     
         10 . The ultrasound system of  claim 1 , wherein the array of transducer elements is further adapted to receive ultrasonic echo signals;
 wherein the diagnostic imaging modality further comprises the ultrasound system performing the therapy, and further comprising:   a user control adapted to control an ultrasound image graphic, wherein the vascular map further comprises a therapeutic beam vector graphic adapted to indicate a location of a therapy site in an ultrasound image in response to the user control.   
     
     
         11 . The ultrasound system of  claim 10 , further comprising a treatment program which is adapted to determine a therapy beam steering direction and a focal depth in response to the user control of the therapeutic beam vector graphic. 
     
     
         12 . The ultrasound system of  claim 11 , wherein the treatment program is further adapted to determine a sequence of therapy beam transmission in response to the vascular map. 
     
     
         13 . The ultrasound system of  claim 11 , wherein the treatment program is further adapted to determine a pause between sequences of therapy beam transmission in response to the vascular map. 
     
     
         14 . The ultrasound system of  claim 11 , wherein the treatment program is further adapted to determine a number of therapy beams transmitted in a sequence in response to the vascular map. 
     
     
         15 . The ultrasound system of  claim 11 , wherein the treatment program is further adapted to determine a spacing between successively transmitted therapy beams in response to the vascular map. 
     
     
         16 . The ultrasound system of  claim 1 , wherein the diagnostic imaging modality is selected from the group consisting of computed tomography, computed tomography angiography, angiography, magnetic resonance imaging, and ultrasound imaging.